Vacuum booster for internal-combustion engines



Oct. 28, 1952 c, LME 2,615,299

VACUUM BOOSTER FOR INTERNAL-COMBUSTION ENGINES i Filed Oct. 15, 1948 3 Sheets-Sheet 1 J. C. HOLMES 2,615,299

3 Sheets-Sheet 2 Inventor,

w m *M a n A WB- m www EQN n I. I i z: WM; A? w M Md mm @N m a. W h 2 VACUUM BOOSTER FOR INTERNAL-COMBUSTION ENGINES Oct. 28, 1952 Filed Oct. 13, 1948 Patented Oct. 28, 1952 UNITED STATES OFFICE VACUUM BOOSTER FO-RJNTERNAL- COMBUSTION ENGINES John 0. Holmes, Signal Mountain, Tenn, assign'or' to J. Curtis Manufacturing Chattanooga, Tenn, a corporation of New Jersey Application October 13, 1948, 'Seria-l No.- 54,325-

11 Claims.

This invention relates to an automobile accessory system and particularly. to improved means manifold. becomes so low that the windshield wiper for instance, will slow greatly or come to a complete stop. This many times happens when there exists the necessity for the utmost vision. The same condition obtains when the automobile engine is under heavy load as when going up a hill.

Numerous devices have been suggestedand used for supplying a more or less constant source of vacuum or at least to reduce the variations. Some of these devices have taken the form of an auxiliary vacuum tank which is exhausted continuously by the intake manifold to buildup a reserve for operating the accessories. when the engine is being accelerated or under heavy load. Otherdevices have utilized the exhaust gases from the engine operated through. venturis to augment the vacuum fromthe intake manifold. Various and-other sundry devices have been suggestedand used including auxiliary pumps. One of the biggest disadvantages of these prior devices is the cost of the extra wearing parts. and the attendant necessary maintenance.

The primary object of the present invention is toprovide a I novel means and method for producinga source of'vacuum directly from the intake-manifold which will be simple, tool-proof and-inexpensive in initial cost and .maintenance.

Another object is to provide an automatic .device associated with the intake manifold of a multi-cylindered engine whereby the eflect of the sudden-opening of the throttle will-not appreciably-affect. the vacuum atom or more of the cylinders,:t'he suction of which'is usedtto operate the accessory device.

A still further object is to provide an :automatic device of the type described in which automatic' means are provided for automatically restricting the intake to passage in the cylinder block which feeds see ofthe cylinders of a multi-cylinderengine so that the suction from this passage can .be utilized to operate vacuum operated accessories regardless of the positiono'f the main throttle valve.

Other andfurther objects will become readily.

apparent from the following description when considered in-connection withthe accompanying drawings illustrating an embodiment of the in'- Vention, and which:

:Figure l is a fragmentary diagrammatic eleva-- I tion of an accessory system'in' accordance with the-present invention-applied to a motor vehicle;'

Figure '2 isan enlarged elevation of the invention showing (its manner of attachment to "the intake manifold;

Figure 3 .is a sectional elevation'of the device shown in Figure .1;

Figure 4 is a partial vertical section on'line 4-4- of Figure 2;

Figure .5 is a horizontal section on line 5''5' of Figure 4;

Figure 6 is a partial vertical section of amodified form of the invention shownin'Figures rm 5 inclusive;

Figure 7 is .an enlarged perspective view of regulating cam shown in Figure 3';

Figure 8 is a partial elevational view of a modified .form of the invention;

Figure 9 is a partial horizontal section on line 9--9 of Figure 8.; and

Figure 10 is a partial sectional elevation on line Iii-l0 of Figure 8.

.An embodiment of the invention is shownas applied to an accessory system for motor'vehic'les in which the auxiliary vacuum'device of the present invention is shown as applied'between a suction operated device such as a windshield wiper I and a point on the intake manifold 'z 'of an automotive internal combustion engine Broadly speaking, the invention provides means associated with the intake manifold for restricting the communication between the main intake manifold of the engine and the branch of the manifold which supplies, in some engines, two cylinders, and in other engines 'an' individual cylinder. The invention provides automatic means not only for controlling the communication into one or more of the cylinders of the multi-cylinder engine, but also utilizes a portion of the potential energy of the vacuum existingin these cylinders during the intake stroke of the cylinders to provide directly the sourceofvacuum for the vacuum operated device and to store ,a portion of the energy represented bythe vacuumcondition to actuate a pumping element whichis returned in the opposite direction by spring means whereby the pulsating vacuum condition of the cylinders is converted to a source of steady and constant vacuum for operating the accessory.

Referring to Figure 3, the auxiliary Vacuum device 4 of the present invention is shown attached to the'intake manifold 2 at a point between the main part of the manifold and the branch conduit or passage 2a, into the engine block. It will be readily understood that it is usual in six-cylinder engines for the branches of the manifold such as branch 20., to feed two cylinders of the engine, while in certain other engines each branch of the manifold feeds an individual cylinder. The important feature of the present invention is that it restricts or re-' duces the .communication between the intake to the cylinder or cylinders which is fed by an individual branch of the intake manifold so that the effect of opening the throttle 6 in the carburetor does not reduce the vacuum in the cylinders fed by this particular branch of the intake manifold to the same extent that the vacuum conditions in the other cylinders are affected. The outlet 7 of the carburetor 8 is connected to the inlet 9 of the intake manifold 2 of the engine in the conventional manner. It will be readily understood that the relation between the position of the'throttle 6 and the speed of the engine normally determines the vacuum conditions existing in each of the cylinders. For example, the vacuum conditions existing in the cylinders when the throttle 6 is set for normal operating speed at normal load conditions may be taken as a reference point and therefore if the engine speed should be suddenly reduced by an increased load, it will be readily apparent that the vacuum conditions at the intake of the manifold will be reduced. The vacuum will, of course, be further reduced if the throttle valve is opened further under such conditions. Also, if the engine is idling and the throttle 6 is suddenly opened, the vacuum in the intake mani fol-d will also suddenly decrease. It is under these conditions that the vacuum in the intake manifold will be so reduced that without some auxiliary device such as that made in accordance with the present invention the vacuum will be decreased to a point that the device such as the vacuum operated windshield wiper i will momentarily cease to operate.

The broadest phase of the present invention contemplates that one of the branches of the intake manifold such as that shown at 2a, will be restricted immediately in accordance with vacuum conditions present in the cylinders to which the branch is connected. To this end the auxiliary vacuum device 4 comprises a chamber I0, the lower end of which is provided with a stem H which is adapted to fit into a hollow boss l2 on the intake manifold. As shown in Figure 3, a gate type valve I3 is adapted to move across the-intake manifold to restrict the communication between the main portion of the manifold and the branch 2a. .The valve it is secured to a suitable valve stem [4 which is actuated by a plurality of flexible diaphragms IE and ii. In the illustrated embodiment, the chamber it! is divided into three sections, the lower section being integral with the stem Ii. Each of the sections is provided with suitable flanges which may be bolted together with the diaphragms l6 and I1 therebetween in accordance with wellknown practice. The upper end of the valve stem M is threaded and the diaphragm I6 is positioned relative thereto by means of suitable nuts I8 and I9 and respective washers 2| and 22. Likewise the flexible diaphragm ll is positioned on the upper end of the valve stem by means of nuts 23 and 24 and respective washers 2B and 21.

The central section of the chamber H? between the diaphragms It and I? is open to the atmosphere through the aperture 28. The primary purpose of the lower diaphragm It is to serve as a means for sealing the valve I3 and the valve stem I 4 against the atmosphere, the diaphragm I! being relied upon to provide the action of this device. It is for this reason that the lower diaphragm I8 is smalled in diameter than the diaphragm I? so that the force acting on the diaphragm I'l will always predominate over any force on the diaphragm It. The valve stem [4 is provided with a suitable guide at 29 and the valve stem 14 is provided with a longitudinal bore Ma which is in communication with the upper transverse bore 14b and lower transverse bore 32 so that that portion of the chamber below the diaphragm l6 will always be in communication with a transverse bore 32 which is subject to the vacuum conditions in the branch passage 2a. A suitable spring 33 is provided between the valve stem guide 29 and the valve [3 and normally urges the latter to its lowermost position across the opening in the intake manifold, it being understood that the force of vacuum acting on the upper side of the diaphragm I! always opposes the action of the spring 33. The upper dome-shaped portion section Illa of the chamber I0 is provided with a suitable radial boss 34 provided with an opening, the outer end of which is screw-threaded at 36 and the inner end of which is reduced in size to provide a seat 3'! for a ball check valve 38. A suitable spring 39 is arranged between the ball check valve 38 and a suitable nipple 4| which is attached to a suitable conduit 42, the other end of which is suitably connected to the lower section lb of the chamber Ii]. The space in the upper part of the chamber between section Ida and the diaphragm I? is connected by means of a conduit $5 to the windshield wiper i (or any other vacuum operated device).

It will be readily apparent from the above description that the windshield wiper l is connected with the branch 2a of the engine intake manifold through the conduit 65, the upper part of the chamber Ill, ball check valve 38, conduit 42, the lower part of the chamber between the lower section I01) and the diaphragm lathe hollow valve stem [4 and the orifice 32. Therefore, when the engine is operating, vacuum will be applied to the windshield wiper i. The spring 33 is adjusted so that it is preferably calibrated or adjusted so that during normal vacuum con ditions, that is, when the engine is operating in its normal range of speeds and the throttle 6 is set accordingly the force of the vacuum acting on the upper side of the diaphragm it will be such as to overcome the force acting on the underside of the diaphragm is and the force of the spring 33 so that the valve i3 will be in its uppermost position. Under these conditions the windshield wiper will be operated directly by the normal vacuum in the intake manifold 2. In the event the engine is subjected to an increase in load, or the throttle is suddenly opened or any other conditions take place which increase the pressure at the inlet 9 to the intake manifold with aconsequent lowering of the vacuumjat the branch passage 2a, the force of the spring 33 will tend to lower the valve |3 across the opening into the branch passage 2a to restrict the opening thereinto and thereby produce a vacuum which is suflicient to maintain the operation of the windshield wiper. It will be readily apparent that the vacuum in thebranch passage 2a will vary over a very wide range, having itslargest value when the piston is on the suction stroke and will be almost non-existent when the piston returns on the compression stroke. Therefore it would not be practical to operate a vacuum operated device directly from the vacuum existing in. branch passage 2a if it is desired to maintain continuous and steady operation. Accordingly, with the present, invention, advantage is taken of the potential energy in the suction developed at the branch passage 2a on the down stroke of the piston to store up potential energy by compressing the spring 33, through the action of the vacuum on the upperside of the diaphragm i! so that during the compression stroke when the suction at branch passage 2a is greatly reduced the spring 33 will return the diaphragm, and consequently the valve |3, to the lower position, the ball check valve 3B closing and the downward movement of the diaphragm serv-= ing as a vacuum pump to exhaust air from the conduit 45 and maintain the windshield wiper in operation until the piston again starts on its suction stroke. It will be readily apparent that with the proper calibration of spring 33 and the appropriate relative sizes of the diaphragms that the valve l3 and the diaphragms will automatically move the appropriate amounts to maintain the vacuum conditions on the windshield wiper. For instance, during the normal setting of the throttle 6 when the engine is operating in its normal range of speeds, the vacuum acting on the upper side of the diaphragm will be sufficient. to maintain the spring 33 in compressed condition and the valve |3 in non-restricting relation in the intake manifold.

'In order to limit the movement of the diaphragms I6 and I1 and the valve l3, a suitable adjustable cam may be provided as shown in Figure 3. This cam is carried on a cylindrical stem 5| having an integral enlarged shoulder 52 and threaded end 53 which is engaged by a lock nut'54. The stem 5| extends through a hollow boss 55 in the middle section Inc of the chamber l6 and may be adjusted in any angular position by means of a transverse screw-driver kerf 56. The stem 5| may be held in any desired-adjusted position so that the cam 50 will limit the downward movement of the gate valve l3 by means of the lock nut 54. The primary purpose of the adjustable cam 53 is to predetermine the distance the gate valve l3 can move downward across the opening in the branch passage 2a of the intake manifbld, thereby predetermining the maximum vacuum applied to the vacuum operated device such as the windshield wiper I. It will be readily appreciated that the more the gate valve |3 restricts the opening in thebranch passage 20, of the manifold, the greater will be the vacuum applied through the auxiliary vacuum device.

Instead of the non-adjustable spring 33 shown in Figure 3, the device may be provided with an arrangement whereby the setting of the spring may be varied for the purpose of varying the degree of vacuum applied to the vacuum operated device within the maximum which is determined by the setting of the cam 50. To this end the construction shown in Figure 6 can be substituted for that shown in Figure 3. In Figure 6 the upper section of the chamber l3 which corresponds generally to the upper section |0a of Figure 3, is provided with a hollow boss 6| having a bore which is screw threaded and adapted to receive adjustable cap screw 62, the end of which is provided with a suitable washer 63 which in turn is engaged by a spring 64, the lower end of which rests on the upper side of washer 26 adjacent the diaphragm H. A suitable lock washer 64 is provided for locking the cap screw in predetermined adjusted position. In this modified form the nipple to which the conduit 45 is attached is placed to one side of the center of the upper section 60 as shown. It will be readily apparent from the above description that by adjusting the cap screw 62 and then looking it in fixed position, the force of the spring 64 acting on the upper side of the diaphragm I! may be readily varied.

It is desired to emphasize here that one of the important features of the present invention is that the auxiliary vacuum device 4 comes into play and operates only when its operation is needed. For instance, when the control valve on the vacuum operated windshield wiper is closed and the engine is operating in its normal range of speeds and the throttle 6 is set accordingly, the force of the vacuum acting on the upper side of the diaphragm will be such as to overcome the force acting on the under side of the diaphragm l3 and the force of the spring 33 so that the valve |3 will remain in its uppermost position. When the control valve on the windshield wiper is open to initiate the operation of the windshield wiper, the windshield wiper motor, through the conduit 45 and the auxiliary device 4 will be in direct communication with the opening in the branch 2a of the intake manifold and if the vacuum is sufiicient to maintain the operation of the windshield wiper, the vacuum above the diaphragm I! will be suflicient to maintain the valve l3 substantially at the upper end of its stroke. In the event the vacuum in the branch passage 2a of the intake manifold drops due to a change in the position of throttle 6 with respect 'to the engine speed, the vacuum force acting on the diaphragm will be decreased'and the spring 33 will move the gate valve l3 to such a position as to maintain the vacuum at the windshield wiper substantially constant. At high engine speeds with the throttle 6 in open position; the flow of air through the vacuum operated device such as the windshield wiper I, will produce such a condition in the auxiliary vacuum device 4 that the valve I3 will remain in a substantially stationary position. However, at low engine speeds with the throttle 6 in the open position, there will be a substantial variation in the vacuumexisting in the branch passage 2a of the intake manifold and therefore the diaphragms l1 and IE will tend to vary their positions and that of the valve |3 in immediate response to the vacuum cause the diaphragm I! to move upward and compress the spring 33, thereby storing potential energy in the spring which is released when the vacuum begins to decrease so that the spring moves the diaphragm downward to maintain a substantially constant vacuum on the windshield wiper I.

A modified form of the auxiliary vacuum device is shown in Figures 8, 9 and 10, in which the actuating device would be substantially identical to that shown in the previous modification, the modification being primarily in the type of valve which would be substituted for the gate type valve I3. Referring specifically to Figure 8, it will be noted that the section of the actuating device designated by the referencenumeral 16 which corresponds to the lower section Nib of the previous modification, is provided with a stem H which is provided with plunger guides 72 and 13. A plunger 14 which corresponds to the valve stem M of the previous modification is adapted to slide.

in the plunger guides 12 and "E3. The plunger M has attached to its outer ends diaphragms corresponding to diaphragms I6 and l I of the previous embodiment. Instead of the gate type valve l3, a suitable butterfly valve 16 is mounted in an insert Ti between the end of one of the branches 20a of the conventional intake manifold and the opening in the side of the engine block which leads to the combustion chamber of one, or two of the engine cylinders in the case of a sixcylinder engine. In Figure 8 the passage 18 in the cylinder block is shown as leading directly to the combustion chamber for a single cylinder. It will be readily understood that in attaching this auxiliary vacuum device to a conventional motor, inserts or spacers Ha of the same width as spacer i! would be provided between the other branch passages and the openings in the cylinder block leading to the different cylinders. The insert'll' has integral therewith a hollow cylindrical stem 19 and a housing 8| which encloses the mechanism for operating the butterfly valve T6.

The upper end of the casing BI is provided with an assembly and inspection plate 82. This plate is sealed to the top of the casing by means of suitable gasket 83 and is held in place by suitable screws 84. The gasket seal is necessary because the casing forms a part of the vacuum channel between the engine cylinder and the vacuum operated device such as the windshield wiper. The housing 8! is also provided with a suitable boss 86 into which the stem H is suitably threaded in sealed engagement. The butterfly valve 76 is carried on a vertical valve shaft 81 to the upper end of whichis attached a suitable bell crank 88. The bell crank 88 is attached to the plunger 14 by means of a suitable link 89. The valve shaft 81 is provided with a central bore 90 which communicates with a transverse bore SH so that the casing 8! is always in communication with the passage 18 in the cylinder block. It will be ap parent from Figure 9 that when the plunger 14 is moved to the right the bell crank arm 88 will be moved in a clockwise direction which carries with it the butterfly valve 16. Preferably the butterfly valve 16 is slightly smaller than the opening in the intake in which it is located and the transverse bore 9| is provided to prevent complete isolation of the passage 78 in the cylinder block from the branch passage 20a of the intake manifold. It will be readily understood that the operation of this device would be very similar to the device of the embodiment previously described, it being understood, of course, that the plunger guides 13 and 12 are provided with the necessary apertures 92 so that the interior of the casing 8 l, the longitudinal bore of the valve shaft 81, and the transverse bore 9| are in direct communication with the passage 18 of the engine. The actuating device 40 in all other respects may be identical with the actuating device 4 previously described including the modification shown in Figure 6. Likewise it will be understood that the operation will be identical, the diaphragms of the device moving the plunger 14 back and forth to rotate the butterfly valve 16 instead of moving the gate type valve into and out of the branch passage of the intake which feeds one or two engine cylinders. The form of the invention shown in Figures 8 to 10 inclusive,- is primarily adapted for attachment to vehicle motors which are already in use because it can be attached without modifying in any respect whatever the intake manifold; it being necessary only to remove the conventional manifold 28 and insert the spacers Ti and Ha. Although in the embodiment of the invention described above, a gate type and butterfly valves are shown, itv will be obvious to those skilled in the art that other devices may be used which will reduce the turbulence in the flow and at the same time restrict the communication between the main part of the intake manifold and the branch passages to the cylinder block and also supplement the vacuum produced by the. cylinder.

Such devices might embody the principles of a Venturi throat.

From the foregoing description it will be readily apparent that the present invention provides a novel auxiliary vacuum devicewhich will produce a substantially constant source of vacuum, or at least asource of vacuum which is sufficient to operate the accessories of the automobile regardless of the variations in vacuum existing at the inlet 9 of the intake manifold of the engine. The auxiliary vacuum device does this by restricting the communication between the main part of the intake manifold and one of the branch passages of the intake manifold which feeds the individual cylinders or two cylinders in the case of the usual six cylinder engine so that the sudden opening of the carburetor throttle does not nullify the vacuum existing at the branch to one of the intake cylinder block openings to which the vacuum operated device, such as a windshield wiper, is connected. Also the present auxiliary vacuum device effectively operates as a pump when necessary when the engine is operating at very low speeds by storing a portion of the potential energy of the suction stroke in the spring 33 so that when the vacuum falls between piston strokes the diaphragm ll will be pulled down, closing valve 38 and exhaust air from the windshield wiper. Also it will be understood that under any conditions where a vacuum operated device is energized through the auxiliary vacuum device of the pres ent invention, which requires a relatively high vacuum, regardless of the operating conditions of the engine any tendency to reduce the vacuum above the diaphragm I 1 will automatically cause the gate type valve I3 or the butterfly valve 16, whichever type is used, to operate to restrict the opening between the intake manifold and the engine cylinder so as to maintain the proper operating vacuum which as previously described can be varied by varying the loading or strength of either the spring 33 or the spring 65 v The invention described herein'is primarily adapted for use with a multi-cylinder four cycle engine as will be obvious from the above description.

Although'the invention has been described in considerablel'detail, it" will be apparent to those skilled in" the art that many variations are possible-without departing from the inventive concept.- fitistherefore desired that the invention not be .limited except insofar as is made necessary by Z the prior art andb y the appended claims.

T'What is claimed is:

.iflInIcombination with a multi-cylinder-intern'al combustion engine having a main intake 1. manifold provided with a plurality of branches for supplying explosive charges to the different cylinders, a suction operated accessory, a suction line connecting the accessory to one of said branch passages, valve means forrestricting the communication between one of said branch passages and themain intake manifold and a pressure dif-r ferential element subjected to the vacuum in said suction line and coupled'to said valve means for varying passage restriction" in said one branch passage by said valve means on occurrence of H pressure differentials in said suction line.

; ;2. An auxiliary vacuum device for supplying vacuum operated devices, operable by the suction produced in a suction line connected to the intake manifold of an engine comprising a housing,. a movable diaphragm within said housing,

one side of said diaphragmbeing open to atmospheric pressure and theother side of said pdiaphragm being subjected to the vacuum in said suction line, resilient means coupled to said diaphragm to be compressed by the force of vacuum acting on said diaphragm and valve means in said intake manifold for restricting the same on reductionv of the vacuum acting on said diaphragm, whereby when the vacuum on said diaphragm decreases said resilient means will operate said diaphragm and said valve means to augment the vacuum in said suction line.

3. An auxiliary vacuum device for connection in the line between a source of variable vacuum coupled with said pressure differential element and actuated on occurrence of a high vacuum acting on said element and consequent movement of said element to store potential energy and to reverse movement of said element on relative decrease in the vacuum acting thereagainst to augment the vacuum of said source by such reverse movement of said element.

4. In an auxiliary vacuum devicefor suctionoperated accessories operable by the suction produced in a connecting line coupled to the intake manifold of an internal combustion engine, the combination of a housing, a flexible diaphragm located within said housing and exposed on one side to the atmospheric pressure and on its other side to the pressure within said connecting line, potential energy storage means connected to said diaphragm and actuated by movement of said diaphragm in response to a vacuum thereon coupled from said connecting line to convert a portion of the potential energy represented by the pressure differential on the opposite side of said diaphragm into mechanical ener y, said potential energy storage means reversing the movement of said diaphragm in response to a reduction of differential pressure in said connecting lineto augment the vacuum of said source by the reverse movement of 'said diaphragm,

, 5. An auxiliary vacuum device-.'connected in a operated device, for the purpose of "augmentin the vacuum of the source, saidauxiliaryvacuum device, comprisinga housing, a diaphragm in Said housing, oneside of said diaphragm being subjected to atmospheric pressure andltheo'ther side thereof being subjected to the pressure in W said suction line, potential energy storage means connected to said diaphragm and actuated by movement of said diaphragm in response, to a vacuum in said suction line to convert a portion of the force acting on said diaphragm into "p otential mechanical energy, Said energy storage verse movementofs'aiddiaphragm.

means reversing movement of said diaphragm when the pressure 'diiierentialon said diaphragm is reduced to augment said source of vacuum through pumping action resulting from the re- 6. In an auxiliary vacuumdevice for suctionoperated accessories operable by the-suction pro- Zduced in'a connecting linecoupled to theintake manifold of an internal combustion engine, the combination of a housing, a flexible diaphragm located within said housing onesidefof which isexposed. to the atmospheric pressure. and the other side of which is subjected to the suction in said connecting line, a check valve in the side'of said line between said auxiliary vacuumvdevice and the intake manifold of the engine, potential mechanical energystorage means connected to said diaphragm and actuated by movement of said diaphragm in response to a vacuum in said suction line to store aportion of the energy represented by movemen'ts of said diaphragm under the action of the suction in said intake manifold, said energy storage means reversing movement of said diaphragmwhen the vacuum in-said manifold decreases whereby the, reverse movement of said diaphragm causes the checkvalve to close .and the movement of the diaphragm serves as a source of'vacuum energy for said accessoryv through pumping action resultingfrom the reverse movement of said" diaphragm.

7. In combination with a multi-cylinderlinter- "nal' combustion engine having a main intake 'manifold provided with a plurality of branches for supplying explosive charges to )the different cylinders, a suction operated accessory, a suction line connecting said accessory ,to one ,ofsaid ,br'an'ches yalve means for restrictingQthe-com- ,munication between said main intakemanifold and said branch, an auxiliary vacuum device connected in said line between said accessory and said one branch passage of said intake manifold,

a check valveiin said line between said auxiliary vacuum device and said manifold adapted to close against the pressure in said manifold, said auxiliary vacuum device comprising a housing,

a differential pressure element in said housing,

one side of which is open to the atmospheric pressure and the other side of which is subjected to the suction in said line, potential mechanical energy storage means connected to said differential pressure element,.said valve means also being connected to said differential pressure element whereby movement of said element in response to the suction in said line will simultaneously store potential mechanical energy and control said valve means and upon decrease in vacuum in said line said potential energy storage means will force said differential element in such 'saidline between said auxiliary vacuum device and said manifold adapted to close against the pressure in said manifold, automatic valve means for restricting the communication between said main intake manifold and said branch, said auxiliary vacuum device comprising a differential pressure element, one side of which is open to the atmospheric pressure and the other side of which is subjected to the suction in said line, potential energy storage means intercoupled with said differential pressure element and means intercoupling said pressure dif ferential element and said value means whereby movement of said differential pressure element in response to a differential pressure in said suction line stores potential mechanical energy which reverses the movement of said differential pressure element when the pressure difierential decreases.

9. A combination with a multi-cylinder combustion engine having, a main intake manifold provided with a pluralityof. branches for supplying explosive charges to the different cylinders, a suction operated accessory, a suction line connecting said accessory to one of said branches, an auxiliary vacuum device connected in said .line between said accessory and said one branch of said intake manifold, a check valve in said line between said auxiliary vacuum device and said manifold to close against the pressure in said manifold, said auxiliary vacuum device comprising a housing, a diaphragm in said housing, one side of said diaphragm being subjected to atmospheric pressure and the other side thereof being subjected to the pressure in said line, valve means for restricting communication between said main intake manifold and said branch operatively connected to said diaphragm, spring means biasing said diaphragm to oppose the force of suction on said diaphragm, a suction in said manifold normally moving said diaphragm to compress said spring and simultaneously to increase the communication between said main intake manifold and said one branch, whereby a reduction in said suction permits said spring to bias said diaphragm connected to said valve means to restrict the communication beand to simultaneously augment the vacuum in 'said line between said check valve andsaid ac- 10. An auxiliary vacuum device for supplying vacuum operated devices adapted to be operated by the suction produced in a suction line connected to the intake manifold of an engine comprising a housing, a movable diaphragm within said housing, one side of said diaphragm being subjected to the vacuum in said suction line, valve means coupled to said diaphragm for restricting passage in said suction line, spring means coupled to saiddiaphragm resiliently urging said diaphragm and valve means intercoupled therewith in suction line passage restricting position, the vacuum in said suction line normally urging said diaphragm in oppositween said main intake manifold and said branch tion to said spring means to store potential en'- ergy therein, said spring means biasing said diaphragm to restrict passage opening'in said suction line and augment vacuum therein through consequent movement of said diaphragm on occurrence of a pressure differential in said suction line.

a 11. In combination with a multi-cylinder internal combustion engine having a main intake manifold provided with a plurality of branches for supplying explosive charges to the different cylinders, a suction operated accessory, a suction line connecting the accessory to one of said branch passages, intake manifold branch restricting means in said one branch intercoupled with a diaphragm, resilient means coupled to said diaphragm normally urging the diaphragm in a direction to effect increasing. restriction of said one branch by said branch restriction means coupled therewith, and vacuum pressure coupled to said diaphragm from said suction line to oppose the bias of said resilient means and store potential energy in the spring means under normal vacuum pressure conditions in said suction line, whereby said resilient means will bias said diaphragm and intercoupled restriction means to restrict passage in said one branch and augment the vacuum therein on reduction of vacuum pressure on the diaphragm below normal pres- JOHN C. HOLMES.

REFERENCES CITED 'The following references are of record in the .file of this patent;

UNITED STATES PATENTS 

